This invention relates to a caries-preventive composition which, when applied to the mouth, can prevent dental caries by suppressing formation of dental plaque.
Dental plaque firmly adhering to the surface of teeth, is composed of about 70% bacteria, about 20% polysaccharides produced by the bacteria and about 10% food remains. It is said that acids stored in dental plaque decalcify enamel, causing dental caries. Therefore, dental plaque is observed as a cause of dental caries.
Formation of dental plaque is accelerated due to the synthesis of polysaccharides from sucrose by oral bacteria, especially Streptococcus mutans. More specifically, Streptococcus mutans synthesizes adhesive polysaccharides such as dextran and mutan from sucrose through the production of GTF (glucosyltransferase, dextran-synthesizing enzyme). The thus synthesized polysaccharides incorporate Streptococcus mutans as well as other bacteria (viruses), forming dental plaque having a given bacterial bouquet. In addition, bacteria such as Streptococcus mutans produce acids by utilizing various kinds of sugar and the thus produced acids decalcify the surface of enamel by remaining in polysaccharides and bacterial walls.
Accordingly, decreasing the number of Streptococcus mutans in the mouth and suppressing the formation of dental plaque is desired in order to prevent dental caries.
It is known in British Pat. No. 1,505,513 that colonization of Streptococcus mutans in the mouth is suppressed by using mother's milk obtained by immunizing a cow with whole bacterial bodies of Streptococcus mutans.
The present inventors studies antibodies which are included in the antibodies to various antigens derived from Streptococcus mutans and inhibit the colonization of Streptococcus mutans in the mouth. As a result, the inventors found that antibodies contained in antiserum and milk obtained by immunizing mammals with Streptococcus mutans, its cell-wall fraction, fibrous substance fraction, glucosyltransferase fraction and protein antigen fraction have certain degrees of dental-plaque-formation suppressing effect. However, the effect was not necessarily sufficient and a higher effect of suppressing the formation of dental plaque was necessary.